Data

Projected Coordinate System of our project: WGS1984 UTM Zone 17N

The following are data layers extracted from a pre-existing Alexandra Fiord ArcGIS project geodatabase that we renamed with our own naming conventions and imported into our ‘ksj_geodatabase’. Where there are explicit concerns with the layers we used, this is noted.

Data:

  • Aerial photo from 2000 (georeferenced, clipped to study area)
  • Plant community raster from 2000 aerial photo (with the following layers):
    • ‘cassvac’
    • ‘cassdry’
    • ‘dryas’
    • ‘rock’
    • ‘sedge’
    • ‘sand’

Issues with this layer:

This layer was constructed using an image classification tool in ArcGIS. The points were based on ground-truthed observations made by Cassandra Elphinstone, a research assistant on the project, in 2015. The problem was that we weren’t sure of the exact method used by Cassandra and we couldn’t emulate the results with the data she provided to us. We wanted to reproduce an updated map using the orthophoto produced from this past summer, but we couldn’t reliably reproduce the method, and so we aren’t sure how trustworthy these data are. They are fine for the purposes of this project, but perhaps not reliable for more robust analysis.

  • Alex clip mask
  • Aerial photo clip 1989
  • Snow cover DOY 160 from 2000
  • Snow cover DOY 180 from 2000
  • Interpolated temperature maps from 2000 & 2010 (Kriging)

Issues with these layers:

Point data for 2000 and 2010 inconsistent – the points used between years were similar, but not exactly the same. While the technique in which the temperatures were recorded is the same, the locations used in 2010 were typically 10-50 meters off the original points from 2000. The area covered by the 2010 data points is broader than the coverage in 2000, so making comparisons and analyses between the two areas was compromised.

  • Spatial points 2000 & 2010: The spatial points of the temperature data loggers. These points are slightly offset from 2000 to 2010, as noted above.
  • General:
    • Topographic map

      Issues with this layer: We created a DEM using the air photos in PhotoScan, however the elevations were clearly not accurate and were off by ~500m. We therefore had to create a DEM from these elevation lines, which, we realize, is not ideal. We used this DEM to create a solar insolation map.

    • Rivers
    • Glaciers
    • Water